JAK2T875N induces a myeloproliferative disease in a murine bone marrow transplant model. Spleen weight of Balb/C animals (A), hematocrit percentages (B), and white blood counts (C) of C57Bl/6 and Balb/C animals and platelet counts of Balb/C animals (D), analyzed at 150 days after transplantation are shown. Each histogram bar represents the mean value from 5 animals plus or minus SD. Student t test was performed and the P value is indicated when a significant difference (P < .05) between JAK2WT and JAK2T875N animals was observed.